I observed a positive relationship between Sr and £REEs in my limestone geochemistry, and would like to know if there are other indices which could be used to explain such relationship, as interpretation based on Sr has limitations. Secondly, can I use trace elements ratios like Al/K, Mg/Ca, etc (or weathering indices) be used to provide a clue to paleo-climatic conditions? How can this be achieved?
I'd be looking at ratios like Ba/Sr and Rb/Sr (or even maybe [CaO + MgO]/Al2O3) to give an idea of carbonate weathering (in my experience silicate weathering indices like CIA are not suitable for carbonate rocks).
Also make sure you deal properly with compositional closure when looking at these relationships - not using raw concentrations, or even simple transformations, but using log-ratios to remove the potentially misleading effects of fixed-sum closure.
I know a clear linkage between REE and Sr in carbonatites where the REE are accommodated in monazite and Sr bound to strontianite based upon this mineralogical knowledge I can shift my thoughts to REE and carbonate. What makes you think that REE play a significant role in your calcareous rocks. Keep in mind you have very strong crystallographic differences and charge balance is another stumbling block. In weathering zones you have still monazite (LREE) and xenotime (HREE) besides rabdophane, florencite and weinschenkite which are hydrated and Al-bearing phosphate analogues. REE are en vogue but you should try and scout the regime in which they form in a special environment in question.
HGD
The relationship between Strontium (Sr) and Rare Earth Elements (REE) in limestone can be ascertained using various indices. Some of the most commonly used indices are: 1. Sr/REE ratio: This ratio is widely used to determine the relationship between Sr and REE in limestone. The Sr/REE ratio is calculated by dividing the concentration of Sr by the sum of concentrations of all REEs. The Sr/REE ratio is useful in determining the source of the sedimentary rock, as different sources have different ratios. 2. Eu anomaly: Eu (Europium) is a rare earth element that behaves differently from other REEs in sedimentary rocks. The Eu anomaly is calculated by dividing the concentration of Eu by the average concentration of all other REEs. A positive Eu anomaly indicates that the sedimentary rock was derived from a felsic source, while a negative Eu anomaly indicates a mafic source. 3. Ce anomaly: Ce (Cerium) is another rare earth element that behaves differently from other REEs in sedimentary rocks. The Ce anomaly is calculated by dividing the concentration of Ce by the average concentration of all other REEs. A positive Ce anomaly indicates that the sedimentary rock was deposited under oxic conditions, while a negative Ce anomaly indicates anoxic conditions. Other indices that can be used include La/Yb ratio, Sm/Nd ratio, and Nd isotopes. Reference Publications or URLs: 1. GeoScienceWorld: https://pubs.geoscienceworld.org/ 2. ScienceDirect: https://www.sciencedirect.com/ 3. ResearchGate: https://www.researchgate.net/
Strontium element ( Sr) is an essential element that organisms absorb from the seawater column; it is considered a nutrient, and the natural source of strontium represents the weathered rock deposition of aluminosilicate detritus sediments that may also result from increasing in the rubidium–strontium through the deposition in marine environments, and it even the finest fraction of aluminosilicates deposited in the ocean ( Dasch,1969) However, strontium is more concentrated than barium or other elements related to the high dissolved strontium in seawater (Bernat et.al,1972) .
However, Lanthanides elements are called in some references as rare earth metal, and it consists of 15 elements that have atomic numbers between 57 to 71, following the element Lanthanum.
It characterizes Lanthanides as f-block elements, meaning that electrons fill the 4f electron shell .
References :
1-Lanthanum references: https:// HYPERLINK
"https://byjus.com/jee/lanthanides/" HYPERLINK "
HYPERLINK "https://www.thoughtco.com/lanthanides-properties-606651"
2-Bernat.,M., Church., T., Allegre ., C., Barium and strontium concentrations in Pacific and Mediterranean sea water profiles by direct isotope dilution mass spectrometry, 1.Introduction, 3. Results, (1972) , published on Earth And Planetary science letters - North-Holland publishing company , Pages: 75, 76 .
3-Dasch., J.E., Strontium isotopes in weathering profiles, deep-sea sediments, and sedimentary rocks , Abstract , (1969) , published in Geochimica et Cosmochimica Acta magazine , Elsevier website https://www.sciencedirect.com/science/article/abs/pii/0016703769901537
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